On Mon, Oct 26, 2020 at 01:47:53PM +0100, Sebastian Andrzej Siewior wrote: > On 2020-10-25 17:56:47 [+0100], Johan Hovold wrote: > > There's a ton of issues with this driver, but this is arguably making > > things worse. A line discipline may call write() from just about any > > context so we cannot rely on tty being non-NULL here (e.g. PPP). > > I wasn't aware of that. I've been looking at the callers each time a > `tty' was passed it looked like a preemptible context (due to mutex / > GFP_KERNEL) and so on. Yeah, the default line discipline only calls in preemptible context (these days), but others do not (e.g. see ppp_async_push()). Johan
